Chunk #6 — Results — Although the majority of fetal brain mQTLs are conserved in adult brain regions, there are fetal-specific genetic effects on DNA methylation at certain loci
We next generated mQTL data from three adult human brain regions (prefrontal cortex (PFC), striatum (STR) and cerebellum (CER)) dissected from matched donors (n = 83; 21–96 years old, see Online Methods and Supplementary Table 1) to explore the extent to which fetal brain mQTLs are also present in the adult brain. Using a replication mQTL significance threshold of P < 1×10−5, the majority (83.46%) of fetal brain mQTLs are present in at least one of the tested adult brain region (Supplementary Table 9 and Fig. 2a), and there is a highly-significant overall correlation of individual mQTL effect sizes between fetal brain and each of the individual adult brain regions (PFC: r = 0.911, P < 2.2×10−16; STR: r = 0.899, P < 2.2×10−16; CER: r = 0.835, P < 2.2×10−16) (Supplementary Fig. 4) across all Bonferroni-significant fetal brain mQTLs, even in mQTLs that do not meet our replication threshold (Supplementary Fig. 5). Of note, fetal brain mQTLs that do not replicate in adult brain are characterized by significantly lower effect sizes across all brain regions, including the fetal brain
